Hoàng's 3-divisibility conjecture for even-hole-free graphs

Let a hole be a chordless cycle of length at least four; it is even if its length is even. For an integer k2k\geqslant 2, a graph GG with at least one edge is kk-divisible if, for every induced subgraph HH with at least one edge, V(H)V(H) can be partitioned into kk sets, none of which contains a maximum clique of HH. Hoàng's conjecture. Every even-hole-free graph is 33-divisible. This conjecture concerns structural decompositions of even-hole-free graphs and the resulting chromatic bounds; the supplied text gives no resolution, so its status remains open.

Sources & referencesView supporting material

Primary source

Hongzhang Chen, Kaiyang Lan and Wenlong Zhong, “On two conjectures of Hoàng”, arXiv:2605.09293 (2026).

Additional references

4 papers in this index state this conjecture (2017–2026). The statement above is taken from the most recent of them; the others are arXiv:2506.12660, arXiv:2110.12710, arXiv:1705.05911.

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.